Process and apparatus for fluidized catalytic cracking of a hydrocarbon feed

Abstract

An improved apparatus and method for the fluidized catalytic cracking (FCC) of hydrocarbons. Turbulence generation means disposed on the internal surface of an FCC riser-reactor are utilized to provide for a more uniform catalyst flow pattern within the riser-reactor and to thereby provide for a better conversion and product slate.

That which is claimed is: 
     
       1. An improved fluidized catalytic cracking system wherein the improvement comprises a riser reactor conduit having an interior surface defining an inside diameter, a lift zone, a reaction zone and an injection zone located between said lift zone and said reaction zone with said interior surface of said reaction zone having disposed thereon turbulence generation means for promoting turbulence in the flow of catalyst in said riser reactor conduit, wherein said turbulence generation means includes: a first surface extending from said interior surface and facing an approaching catalyst flow; and   a second surface extending from said interior surface and facing opposite said approaching catalyst flow, and   wherein said first surface and said second surface intersect at a terminal edge distant from said interior surface, wherein the dimension from said interior surface to said terminal edge is less than 10 percent of said inside diameter, and wherein said first surface slopes in the direction of said approaching catalyst flow at an angle between about 30 to 60 degrees and said second surface slopes in an opposite direction of said approaching catalyst flow at an angle between about 5 to 25 degrees.   
     
     
       2. An improved fluidized catalytic cracking system as recited in claim 1 wherein said turbulence generation means are spaced in said reaction zone of said riser reactor conduit at intervals of from about 5 to about 30 of said inside diameter. 
     
     
       3. An improved fluidized catalytic cracking system as recited in claim 2 wherein said turbulence generation means further comprises an engineered ceramic material. 
     
     
       4. An improved fluidized catalytic cracking system as recited in claim 1 wherein said turbulence generation means is located between 2 and 3 feet above said injection zone. 
     
     
       5. An improved fluidized catalytic cracking system as recited in claim 1 wherein the dimension from said interior surface to said terminal edge is less than 7.5 percent of said inside diameter. 
     
     
       6. An improved fluidized catalytic cracking system as recited in claim 1 wherein the dimension of said interior surface to said terminal edge is less than 5 percent of said inside diameter. 
     
     
       7. An improved fluidized catalytic cracking system as recited in claim 1 wherein said first surface slopes in the direction of said approaching catalyst flow at an angle between about 35 to 55 degrees and said second surface slopes in an opposite direction of said approaching catalyst flow at an angle between about 7.5 to 20 degrees. 
     
     
       8. An improved fluidized catalytic cracking system as recited in claim 1 wherein said first surface slopes in the direction of said approaching catalyst flow at an angle between about 40 to 50 degrees and said second surface slopes in an opposite direction of said approaching catalyst flow at an angle between about 10 to 15 degrees. 
     
     
       9. An improved fluidized catalytic cracking system as recited in claim 1 wherein said turbulence generation means are spaced in said reaction zone of said riser reactor conduit at intervals from about 10 to about 25 of said inside diameter. 
     
     
       10. An improved fluidized catalytic cracking system as recited in claim 1 wherein said turbulence generation means are spaced in said reaction zone of said riser reactor conduit at intervals from about 15 to about 20 of said inside diameter. 
     
     
       11. A process for contacting a hydrocarbon feedstock with hot solid particles within a riser reactor of a fluidized catalytic cracking system said process comprises: providing an elongated conduit having an interior surface, defining an inside diameter, a lift zone, a reaction zone and an injection zone located between said lift zone and said reaction zone with said interior surface of said reaction zone having disposed thereon turbulence generation means for promoting turbulence in the flow of said hydrocarbon feedstock with hot solid particles within said reaction zone, wherein said turbulence generation means includes a first surface extending from said interior surface and facing an approaching catalyst flow, and a second surface extending from said interior surface and facing opposite said approaching catalyst flow, wherein said first surface and said second surface intersect at a terminal edge distant from said interior surface, wherein the dimension from said interior surface to said terminal edge is less than 10 percent of said inside diameter, and wherein said first surface slopes in the direction of said approaching catalyst flow at an angle between about 30 to 60 degrees and said second surface slopes in an opposite direction of said approaching catalyst flow at an angle between about 5 to 25 degrees; introducing said hot solid particles into said lift zone wherein said hot solid particles are fluidized with a fluidization gas and lifted into said injection zone;   introducing said hydrocarbon feedstock into said injection zone wherein said hot solid particles are mixed with said hydrocarbon feedstock; and   passing said hydrocarbon feedstock with said hot solid particles into said reaction zone.     
     
     
       12. A process as recited in claim 11 wherein said turbulence generation means are spaced in said reaction zone of said riser reactor conduit at intervals of from about 5 to about 30 of said inside diameter. 
     
     
       13. A process as recited in claim 12 wherein said turbulence generation means further comprises an engineered ceramic material. 
     
     
       14. A process as recited in claim 11 wherein said turbulence generation means is located between 2 and 3 feet above said injection zone so as to prevent said hydrocarbon feedstock flow from streaming ahead of said hot solid particles. 
     
     
       15. A process as recited in claim 11 wherein said hydrocarbon feedstock has a residence time of 1 to 3 seconds within said elongated conduit. 
     
     
       16. A process as recited in claim 11 wherein said hydrocarbon feedstock has a residence time of 1.5 to 2.2 seconds within said elongated conduit. 
     
     
       17. A process as recited in claim 11 wherein said hydrocarbon feedstock has a residence time of 1.75 to 2.0 seconds within said elongated conduit. 
     
     
       18. A fluidized catalytic cracking system comprising a riser reactor conduit having an interior surface defining an inside diameter, a lift zone, a reaction zone and an injection zone located between said lift zone and said reaction zone with said interior surface of said reaction zone having disposed thereon a plurality of protrusions for promoting turbulence in the flow of catalyst in said riser reactor conduit, wherein said protrusions include: a first surface extending from said interior surface and facing an approaching catalyst flow; and   a second surface extending from said interior surface and facing opposite said approaching catalyst flow,   wherein said first surface and said second surface intersect at a terminal edge distant from said interior surface, wherein the dimension from said interior surface to said terminal edge is less than 10 percent of said inside diameter, and wherein said first surface slopes in the direction of said approaching catalyst flow at an angle between about 30 to 60 degrees and said second surface slopes in an opposite direction of said approaching catalyst flow at an angle between about 5 to 25 degrees.   
     
     
       19. A fluidized catalytic cracking system as recited in claim 18 wherein said protrusions are spaced in said reaction zone of said riser reactor conduit at intervals of from about 5 to about 30 of said inside diameter. 
     
     
       20. A fluidized catalytic cracking system as recited in claim 19 wherein said protrusions further comprise an engineered ceramic material.